Geology

Weaver describes the geologic province of Anacapia as consisting of the islands of San Miguel, Santa Rosa, Santa Cruz, and Anacapa, plus the western portion of the Santa Monica Mountains. The province is to the south of the Santa Barbara embayment, and north of the Catalinia geologic province. Mesozoic in origin, the Anacapia province consists of Late Cretaceous to Miocene age marine sedimentary up to 23,000 feet thick, including 8,000 feet of volcanic rocks, overlain by Pleistocene terrace formations. Aligned with the Santa Monica mountains, the Northern Channel Islands form a mountain system 130 miles long. This island chain appears to be a faulted east-west trending anticline. Major faults include the Santa Cruz Island Fault and the Santa Rosa Island Fault.

During the Late Pleistocene, all of the islands were much closer to the mainland due to lower sea levels, and between 11,000 and 20,000 years BP, the islands remained connected to each other as Santa Rosae. The Pleistocene mammoths swam to Santa Rosae. However, the pygmy mammoth underwent dwarfing as the Channel Islands became isolated. Another species which became extinct was the "giant" mouse. Mammoth remains include those of Mammuthus columbi, while the remains of Mammuthus exilis have been found on San Miguel, Santa Rosa, and Santa Cruz, ranging in age from 12,840 to >47,000 YBP. The 1994 Mammuthus exilis discovery on Santa Rosa near Carrington Point, was the first example of an in situ, almost complete, articulated skeleton.

Other geologic features of note on the islands include beachrock, eolianite, and caliche pseudomorphs. However, only three land mammals are native to the islands, one of which is the deer mouse (Peromyscus maniculatus) which is known to carry the sin nombre hantavirus. The spotted skunk and island fox also are native, with the fox endemic to the islands. The island fence lizard The visitor center contains several exhibits including an aquarium, that provide information regarding all five islands, native vegetation, marine life and cultural history. Also, visitors can enjoy a short film, free of charge, that provides an overview of all five islands. The visitor center is open every day, except Thanksgiving and Christmas, from 8:30AM–5:00PM. There is also a gift shop where souvenirs can be purchased. The average annual visitation to the mainland visitor center was around 311,000 in the period from 2009 to 2018, with 366,250 visiting in 2018.

The Channel Islands can be reached by private boat, or the official concessionaire, Island Packers. Based on ocean conditions and ferry availability, Scorpion Anchorage on Santa Cruz Island is the most visited area in the park for day and camping visitors. Camping visitors arrive at Prisoners Harbor

  • research diving boat Pacific Ranger 56 ft.
  • Sea Ranger II 58 ft.
  • Ocean Ranger 100 ft.
  • Sea Ranger 41 ft (retired).

See also

  • California coastal sage and chaparral ecoregion
  • Channel Islands of California
  • List of California Channel Islands wildlife
  • List of national parks of the United States
  • National parks in California
  • When the Killing's Done – a novel by T.C.Boyle

References

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  • Official site: Channel Islands National Park
  • NPS Public domain pictures of park
  • North America’s “Galapagos”, satellite photos and features of the National Park, at NASA Earth Observatory